The present invention relates to a vehicle with a drivers cab comprising a driver unit with a vertically suspended floor structure including; means for vehicle steering control, means for vehicle speed control and a driver's seat, wherein the cab is provided with a deformation zone behind the driver unit for absorbing force in case of a frontal collision.
The driver seating arrangement for heavy trucks and heavy construction vehicles usually comprises a seat with suspension for driver comfort. One disadvantage with seat suspension is that the seat moves up and down when driving over road surface deviations, in relation to the steering wheel, the pedals and other vehicle controls. The vertical movements can make it more difficult to control a heavy vehicle in a tight situation.
U.S. Pat. No. 3,774,711 discloses a driver's cab with a seat mounted as a driver unit on a platform that includes a steering wheel and foot pedals. The platform is mounted to the cab floor via a vertical suspension system. An advantage with this type of driver unit is that the seat can move vertically together with the steering wheel and the foot pedals when driving over road surface deviations. A disadvantage with this type of driver unit is that it is not well anchored to the cab structure with respect to its ability to protect the driver by absorbing crash forces.
DE 1680095 discloses a bus with a driver unit comprising a seat, a steering wheel and foot pedals. This driver unit is designed to protect the driver by moving horizontally backwards when subjected to a frontal crash force. However, this driver unit is not suspended for vertical motion.
It is desirable to provide a vehicle with a driver unit suspended for vertical motion, which also can protect the driver by providing controlled backward movement to absorb frontal crash forces.
According to an aspect of the present invention, a vehicle is provided with a driver's cab comprising a driver unit with a vertically suspended floor structure including means for vehicle steering control, means for vehicle speed control and a driver's seat, wherein the cab is provided with a deformation zone behind the driver unit for absorbing force in case of a frontal collision. According to an aspect of the invention, a horizontal beam belonging to the cab frame structure is positioned in front of the driver unit, and means are provided for positive locking the beam to the driver unit in case a frontal collision causes the beam to contact the driver unit. By locking the driver unit to the cab frame structure, it is possible to reduce vertical movements and to control the horizontal movement of the driver unit through the deformation zone.
The horizontal beam is preferably the lower member of a windscreen frame.
Preferably, the cab is provided with a double floor containing the suspension for the driver unit.
Advantageously, the double floor contains force absorbing means in said deformation zone for providing a controlled rearward movement of the driver unit in case of a frontal collision. Said force absorbing means may comprise two or more force absorbing crash tubes mounted in parallel extending between said driver unit and the cab frame structure.
According to an advantageous embodiment of the invention, the means for locking said beam to said driver unit comprises conical contact surfaces on the beam facing the driver unit and corresponding contact surfaces on said driver unit facing the beam, to control vertical movement in case of a frontal collision.
Preferably, guide rails positioned behind the driver unit are arranged to control the horizontal movement of the driver unit into the deformation zone as the force absorbing means are compressed.
According to another advantageous embodiment of the invention, the double floor is provided with lateral supports for the driver unit to guide the drive unit into the guide rails in case of a frontal collision.
Further embodiments of the invention are illustrated and explained in the figures.